Many companies have tried in the last decades to remove bones automatically out of food products. The most common attempts have been made to take pin bones out of white fish and salmon fillets. For salmon fillets several companies have been successful in picking out bones from fillets which have been allowed to mature for about 2-4 days after the salmon was slaughtered. Carnitech and Uni-food in Denmark are two of the companies which make such machines. Recently several salmon companies have started to produce a salmon product which is called pre-rigor loins from salmon fillets. The production of those loins require that the pin bones are taken out of the fillets while they are still in rigor. Current methods or machines does not work in this case as the bones are then stuck a lot tighter than in matured fillets.
A similar machine as is used to pick out bones from salmon fillets has been developed by the company Marel and used on white fish fillets including cod, haddock and saithe. The same problems is with this machine as with the pin bone removing machine for salmon that it does not work well on very fresh fish.
More recently the Icelandic company Skaginn attempted to cut pin bones automatically from super chilled fillets with water jet cutting as is described in patent application WO 2006/064521 A1. First of all it is not practical in all cases to super chill the fillets prior to cutting due to extensive cost and space requirement as well as many processor believe it reduces the quality of the products to bring the food to freezing as it changes the properties of the food. Furthermore the super cooling does only generate benefit for a limited number of cases. Skaginn used a regular camera to take a picture of the fillet and estimate based on the image where the bones are. With this method it is not possible to cut out bones from fish fillets with the accuracy and reliability which is required by the industry.
The usage of water jet cutting and a vision system is also disclosed in application U.S. Pat. No. 4,557,019 and then later with minor additions in patent U.S. Pat. No. 4,962,568. In those patents there is however no attempt made to cut food items into sections where selected sections are bone free as other include bones.
The company Trio Food Processing Machinery in co-operation with a Norwegian research agency, SINTEF, tried to cut pin bones automatically from pre-rigour salmon fillets. The idea was to use regular computer vision and then cut the soft root of the pin bones as the force needed to extract the bones is supposedly reduced by that by about 50%. The cut is performed by inserting a long thin knife from the head end of the fillet close to the skin. The knife is inserted in such a way that the tip of the knife follows a trajectory where the tendons are estimated to be located, and thus cuts the tendons. The pin bones can not be seen directly on the outside of the fillet. It was thus necessary to estimate the location of the tendon attachment based on features on surface of the fillet. One alternative in this method could be to detect the bone ends and use those to position the cut. The bone ends are however also often well hidden into the flesh, which makes any detection of them difficult and unreliable. This method has not been successful so far.
U.S. Pat. No. 5,162,016 discloses a method for segmenting an animal carcass by placing it on a mounting vehicle, which forms a portion of a carcass transport system. The mounting vehicle securely holds the carcass and transports it to an imaging station in which a position of a selected bone in the carcass is determined using a first and a second scanner. The first scanner includes two television cameras and the second scanner includes two X-ray tubes.
Before imaging begins, the mounting vehicle or the carcass thereon is positioned in a known location within the imaging station. For instance, a detector, such as photodiode, is positioned within the imaging station to deliver a control signal in response to the carcass or the mounting vehicle reaching a predetermined location. The control signal causes the drive mechanism driving the mounting vehicle to stop the mounting vehicle in the predetermined location. Once in position, the interior and exterior portions of the carcass is scanned.
After the scanning, the mounting vehicle transports the carcass to a cutting station, where pressurized fluid stream containing an abrasive material is directed toward the carcass along a cutting path created by the information from the scanners. At the cutting station, a detector is provided that determines the proper position of the carcass so that the pressurized fluid stream can segment the carcass along the predetermined cutting paths into e.g. primary cuts, such as shank, the round, the rump, the sirloin, the loin, the flank, the rib, the chuck, the plate etc. These primary cuts fall onto a conveyor belt that operates below the carcass.
Based on the above, U.S. Pat. No. 5,162,016 is limited to cutting cattle, pigs and labs carcasses, but not the resulting primary cuts such as the shank, the round, the rump, the sirloin etc., which are subsequently delivered for further butchering or transport to a wholesale outlet.
The inventor of the present invention has appreciated that there is thus a need for food processing apparatus that is capable of automatically processing food item pieces such as said primary cuts resulting from U.S. Pat. No. 5,162,016, but also all kinds of food item pieces such as fish fillets, poultry pieces and the like with the aim of increasing the cutting yield and has in consequence devised the present invention.